The invention starts from a deformable wall made of preferably reinforced plastic.
Deformable walls are required for various conditions of use. For example, deformable walls are applied in wind tunnel testing techniques, in which the wall of a wind tunnel must be deformed, i.e. adapted in such a way that it follows the airflow pattern produced by the model situated in the wind tunnel. This is desirable in order to reduce or to eliminate the interferences of the wall of the wind tunnel on the airstream past the model in the wind tunnel. Furthermore, it is possible with such a deformable wall to cancel out any compression impacts arising on the wall such that they do not in turn strike the model due to reflection. Consequently, this measure also serves for the prevention of wall interferences.
A further area of application of deformable walls is with airplane ailerons, of which the contour or parts of the contour are formed by the deformable wall. Thus it is possible at any time to change the contour of the airplane aileron by deforming the wall, such that the contour can be adapted to correspond to the respective prevailing conditions. This is called a variable curvature. By this means a considerable saving of fuel can be achieved. By deforming the wall, the leading edges of the ailerons can also be changed in such a way that so-called slats are produced for the take-off and landing phase. By this means, complicated adjustment mechanisms are spared and interruptions in the contour are avoided which must be particularly avoided in the development of a laminar aileron.
In the case of large, curved surfaces, for example with parabolic mirrors, such deformable walls are also advantageous since high precision cannot be maintained from the very beginning. By means of later deformation of the wall, which takes place after assemblage, the required precision can then be fulfilled.
A deformable wall of the type described at the beginning is known from the German journal for Aeronautics and Space Research 3 (1979), issue 2, pages 129 to 133. In the article by U. Ganzer "Windkanale mit adaptiven Wanden zur Beseitigung von Wandinterferenzen" ["Wind tunnels with adaptive walls to eliminate wall interferences"], a deformable wall is described which is manufactured from glass fiber-reinforced plastic. A multitude of adjustment devices is provided which are connected to the wall via joints. This deformable wall is used as a wind tunnel wall in order that the airstream in the wind tunnel can be adapted to correspond to the airflow pattern caused by the wind tunnel model. As already described above, by this means wind tunnel interferences can be reduced or eliminated. It is disadvantageous that the size of the construction is relatively large. Due to this, the minimum distance possible between the individual adjustment devices is likewise relatively large, such that fine adjustment of the wall is not possible. In particular when compression impacts occur, this wall cannot cancel out the compression impacts on account of the relatively large distance between supports. It is furthermore disadvantageous that, due to the arrangement of the joints when the wall has been adjusted, a moment is exerted on account of the adjustment devices such that, finally, the adjusted wall exhibits undulations. However, this is undesirable since such undulations in turn affect the airflow past the model to be measured in the wind tunnel.
DE-AS-2,941,404 discloses a measurement section on wind tunnels which likewise has a deformable wall. This deformable wall is circular in cross-section and is manufactured preferably from rubber. In this case too, a multitude of adjustment devices, which are arranged on the circumference in a longitudinal direction, act on the wall and consequently bring about the possibility of deformability. Thus the principle of the deformation of the wall is the same as already described above with all its disadvantages such as limited distance between supports and thus finally also with only low precision of the wall adjustment.